I was sitting down and taking in the beauty of the tank and some of the new work that I was doing when I noticed something strange. As I sat and watched the fish all I saw was a gathering of roughly 5 at first then aprox 10 surfacing and taking in air. This was about 11pm, I observed them surfacing and taking in air, it seemed that they were a bit stressed even with nice size and coloring. I had a stronger air pump in the back of my truck from when I moved my original set of fish. i quickly ran out and made the proper connections to the 2 air stones that I have in the tank and everyone is swimming around happily and not surfacing for air. and it seems that the gill motion has decreased.

My point to it all is that if I had not observed the tank I may have ran into a problem of having to deal with dieing or sick fish.

A water change with low O2 water (like out of a closed water tower, it can be hard predict where water comes from when you turn on the tap). Something that is slowing down oxygen exchange like a pump off or a oily surface film (don't OD melefix or Novaqua or any other oily additive).

Things that use up oxygen such as Prime + high nitrate, a lot of plants in the dark, too many fish/snails/animals for the amount of surface movement. Some "anti-nitrate" or sludge removing additives. A lot of decaying stuff that the bacteria is eating. A lot of bacteria (some bacteria in a bottle will have this effect) or certain algaes. Look for cloudy or off-color water.

Other gases that displace O2 in the water like CO2, HS, etc.

Higher temps because warmer water holds less oxygen.

Anything that hurts a fish's gills will make it need more O2 to get by. So high ammonia, or nitrite, Ich or gill flukes can cause the gasping at the surface symptoms w/o low O2. Fish that have been ammonia-burned in the past should be kept with extra aeration if you can.

Did a test and every thing was with in range basically zero nitrates were a little more than normal.I have not seen them doing the same thing since last night, after I put the stronger pump on they have been fine or at least so it seems.

Whew! disaster averted! I have had that unpleasant experiance once, mine was due to having medicated and the antibiotic killed off the algae which caused...well, you get the picture. This goes to show the importance of really observing your tank behavior and reacting to something not quite right, before it becomes something horribly wrong. Good job!

A friend of mine also was telling me to try and place the output from my canister filters above or close to the surface so the breaking of the plane of the waters surface can and will create more oxygenated water. That I have not done yet I just cranked up the air stones to the tank. Maybe on the next tank cleaning I will do that.

Thanks for your information, it will surely help. Everyone should give time to their respective tanks as observations only drive us to good decisions. The information which you have shared is precious one.